Network does not connect

Hi
There are carriers that cannot be connected to the network. Docomo’s SIM was automatically connected. SoftBank cannot be connected automatically or manually. When I consulted with the dealer, the firmware was provided. I updated it, but the situation hasn’t changed. I consulted with the dealer again, but there was no response. I want to know the solution.

ATI1
Quectel
EC21
Revision: EC21JFAR06A05M4G

AT+COPS=?
+COPS: (1,"SoftBank","SoftBank","44020",7),(3,"KDDI","KDDI","44051",7),(3,"440 52","440 52","44052",7),(3,"440 53","440 53","44053",7),(3,"441 00","441 00","44100",7),(3,"440 11","440 11","44011",7),(3,"KDDI","KDDI","44050",7),(3,"JP DOCOMO","DOCOMO","44010",7),,(0-4),(0-2)

OK
AT+COPS=1,2,"44020",7
ERROR
AT+COPS=1,2,"44100",7
ERROR
AT+COPS?
+COPS: 0

Have you set the APN correctly. Most networks won’t allow LTE network registration without using a valid APN.

thank you. I set the APN and connected to the network normally.
I am wondering if data communication charges will be incurred. I want to receive only voice calls and incoming SMS.

Network registration is not a data connection. I wouldn’t expect you to have any data charges for received calls and SMSs.